Micro-displays are small displays, typically having a display diameter of only a few centimeters intended for viewing by only one person at a time. Often, micro-displays are found in head-mounted virtual reality or augmented reality systems and include a separate micro-display mounted in front of each of a viewer's eyes. Typical micro-display systems include projected or direct-view displays based on liquid crystal or organic light-emitting diode devices.
Micro-displays are typically near-to-eye displays that have very high resolution, for example 2500 dpi or a pitch of approximately 10 microns. Most flat-panel displays have much lower resolution, for example less than 300 dpi and rely on thin-film transistors formed on a flat-panel substrate to operate the liquid crystals or organic light-emitting diodes. However, an organic light-emitting diode display using a micro-transfer printed active-matrix controller chips for each pixel was described in AMOLED displays with transfer-printed integrated circuits published in the Journal of the SID 1071-90922/11/1904-0335 in 2011. Inorganic light-emitting diode displays are also known. U.S. Patent Application Publication No. 2015/0327388 para. [0110] describes micro-transfer printed active components forming pixels in a display that include a controller controlling light-emitting diodes. However, the controller chips can have a size as large as or larger than the high-resolution pixels in a micro-display, making it difficult to maintain a very high resolution.
For some applications, particularly augmented reality applications in outdoor conditions, bright displays are necessary to provide adequate contrast for a user to view projected information. However, LCD devices and OLED devices can have inadequate brightness. Although increased power provided to such devices can increase brightness, increased power can reduce display and battery lifetime. There is a need, therefore, for a micro-display system with improved brightness, display lifetime, and battery life.